Hi Glenn.
Yes, you can hook up a powered subwoofer to your integrated amp using the preouts. If the sub has 2 line level RCA inpouts, just use those. Some newer subs have a single line level RCA input, somtiomes labled "LFE". In this case, get an adaptor with 2 female RCAs on one end and a single male RCA on the other end. Parts Express carries these adaptors.
Use the volume, crossover and phase controls on the sub for bass managemant.
Mike